CN115620689A - Annular spiral acoustic black hole vibration reduction structure - Google Patents
Annular spiral acoustic black hole vibration reduction structure Download PDFInfo
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- CN115620689A CN115620689A CN202211198339.8A CN202211198339A CN115620689A CN 115620689 A CN115620689 A CN 115620689A CN 202211198339 A CN202211198339 A CN 202211198339A CN 115620689 A CN115620689 A CN 115620689A
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- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
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- G—PHYSICS
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- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
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Abstract
The invention discloses an annular spiral acoustic black hole vibration reduction structure, which relates to the technical field of vibration reduction and noise reduction and comprises a central ring, a plurality of Archimedes spiral acoustic black holes and an annular belt, wherein the central ring is made of a high-temperature resistant material; the central ring is sleeved on the surface of the tubular structure to be damped; each Archimedes spiral acoustic black hole is formed by curling the tail end of one-dimensional acoustic black hole around a tubular structure to be damped in an Archimedes spiral mode; the head end of each one-dimensional acoustic black hole is fixed on the surface of the tubular structure to be damped through a central ring, and the head end of each one-dimensional acoustic black hole is uniformly distributed in the central ring along the circumferential direction of the tubular structure to be damped; the thickness of the one-dimensional acoustic black hole decreases exponentially from the head end of the one-dimensional acoustic black hole to the tail end of the one-dimensional acoustic black hole; the damping ring belt is adhered to the outermost layer contour of the Archimedes spiral acoustic black hole, and the ring belts jointly form the outermost layer contour of the vibration damping structure. The invention is suitable for vibration reduction and noise reduction of tubular structures, and has light weight and high temperature resistance.
Description
Technical Field
The invention relates to the technical field of vibration and noise reduction, in particular to an annular spiral acoustic black hole vibration reduction structure.
Background
The development of lightweight structures with high damping performance has been a significant challenge in engineering issues. The essence of the noise generated by the vibration of the structure is the wave phenomenon generated by multiple reflections of the structure at the boundary and the mutual coupling action of the elastic wave and the surrounding acoustic medium. Therefore, one effective means for achieving vibration and noise reduction of the structure is to control the elastic waves in the structure. The current wave control techniques mainly fall into two categories: active control and passive control. Active control generally requires external energy supply, and the design of the system is also complicated, so that the practicability is insufficient at present, and large-scale popularization is difficult. The most common way of passive control is to paste damping materials, but for some large-scale structures, a large amount of damping materials need to be pasted on the surface of the large-scale structures, so that not only is the economic cost increased, but also excessive additional mass is introduced, and the structure is not light.
The Acoustic Black Hole (ABH) effect changes the structure impedance by changing the thickness of the structure according to a certain power law, resulting in a gradual decrease of the propagation speed of the elastic wave in the structure. In the ideal case, when the thickness is reduced to zero, the wave velocity is also reduced to zero accordingly, resulting in a phenomenon of zero reflection and energy concentration of the wave. In actual processing, the thickness cannot be reduced to zero due to the presence of the truncation, but the energy is still concentrated in the region of the minimum thickness of the structure. Therefore, a small amount of damping materials are combined in the energy concentration area, so that the structural loss factor can be effectively enhanced, the energy can be absorbed, and the structural vibration can be reduced.
However, most of the existing acoustic black hole structures (conventional acoustic black hole structures) are beam-shaped and disc-shaped structures, and are mainly designed for flat-plate-shaped structures, that is, mainly designed for vibration perpendicular to a plate surface direction. For a tubular structure (pipeline structure), the vibration direction of the tubular structure has radial vibration (bending vibration) perpendicular to the pipeline direction and also has circumferential vibration (torsional vibration) around the pipeline direction, for multi-directional vibration generated by the non-planar structure (multi-direction, namely, the bending vibration generated along the pipeline direction when the pipeline vibrates, the torsional vibration generated by the pipeline torsion and the bending vibration formed by bending and torsional coupling), the traditional acoustic black hole cannot meet the vibration reduction requirement, namely, the traditional acoustic black hole structure is not suitable for the pipeline structure widely applied in the factory construction and production process.
Most of the existing vibration reduction treatment modes for the pipeline structure are that a layer of damping material is paved on the pipeline, the mode often increases too much mass for the structure, and is not beneficial to the requirement of light weight in production and processing.
In summary, there is a need in the art for a new acoustic black hole structure suitable for vibration reduction and noise reduction of a tubular structure, and achieving the purposes of light weight and high temperature resistance.
Disclosure of Invention
The invention aims to provide an annular spiral acoustic black hole vibration reduction structure, which is suitable for vibration reduction and noise reduction of a tubular structure and achieves the aims of light weight and high temperature resistance.
In order to achieve the purpose, the invention provides the following scheme:
an annular spiral acoustic black hole vibration damping structure comprises a central circular ring, a plurality of Archimedes spiral acoustic black holes and a plurality of annular bands, wherein the central circular ring is made of a high-temperature-resistant material;
the central circular ring is sleeved on the surface of the tubular structure to be damped; each Archimedes spiral acoustic black hole is formed by curling the tail end of one-dimensional acoustic black hole around the tubular structure to be damped in an Archimedes spiral mode; all the one-dimensional acoustic black holes are the same; the head end of each one-dimensional acoustic black hole is fixed on the surface of the tubular structure to be damped through the central ring, and the head end of each one-dimensional acoustic black hole is uniformly distributed in the central ring along the circumferential direction of the tubular structure to be damped; the head end of the one-dimensional acoustic black hole is the thickest end of the one-dimensional acoustic black hole; the tail end of the one-dimensional acoustic black hole is the thinnest end of the one-dimensional acoustic black hole; the thickness of the one-dimensional acoustic black hole decreases exponentially from the head end of the one-dimensional acoustic black hole to the tail end of the one-dimensional acoustic black hole;
the annular belts are adhered to the outermost layer outline of the Archimedes spiral acoustic black hole, and the annular belts jointly form the outermost layer outline of the vibration damping structure; the Archimedes spiral acoustic black hole is used for absorbing and dissipating bending vibration energy and torsional vibration energy generated at any position on the tubular structure to be damped; the annulus is configured to dissipate the bending vibration energy and the torsional vibration energy.
Optionally, the number of the archimedean spiral acoustic black holes is at least 4.
Optionally, the number of zones is at least 4.
Optionally, the number of acoustic black holes of the archimedean spiral and the number of annuli are equal.
Optionally, the expression of the index is h (x) = epsilon x m +h 0 (ii) a Wherein h (x) represents the thickness of the one-dimensional acoustic black hole; ε represents the coefficient; x represents the length of the one-dimensional acoustic black hole; m is a constant and is more than or equal to 2; h is a total of 0 And the thickness of the thinnest end of the one-dimensional acoustic black hole is represented.
Optionally, the annulus is a damping material.
Optionally, the damping material is a 3M damping material.
Optionally, a bolt hole is arranged on the central ring; the bolt holes are used for fixedly connecting the two tubular structures to be damped.
Optionally, the central ring is fixed to the surface of the tubular structure to be damped by gluing or welding.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
the invention discloses a ring-shaped spiral acoustic black hole vibration damping structure, wherein the head end of each one-dimensional acoustic black hole is fixed on the surface of a tubular structure to be damped through a central ring, the head end of each one-dimensional acoustic black hole is uniformly distributed in the central ring along the circumferential direction of the tubular structure to be damped, the tail end of each one-dimensional acoustic black hole is curled around the tubular structure to be damped in an Archimedes spiral manner to form the ring-shaped spiral acoustic black hole vibration damping structure, the head end of each uniformly distributed one-dimensional acoustic black hole is fixed on the surface of the tubular structure to be damped through the central ring, the connection of the ring-shaped spiral acoustic black hole vibration damping structure and the tubular structure to be damped through the rings is realized, the contact surface covers the circumferential surface of the whole tubular structure to be damped, so that the annular spiral acoustic black hole damping structure can absorb and dissipate bending vibration energy and torsional vibration energy generated at any position on the tubular structure to be damped, the vibration energy on the tubular structure to be damped is transmitted to a variable thickness region (the Archimedes spiral acoustic black hole is variable in thickness) of the annular spiral acoustic black hole damping structure made of a high-temperature-resistant material, the vibration and noise reduction characteristics of the acoustic black hole are combined, and the vibration energy is dissipated by combining a damping girdle adhered to the variable thickness region, so that the effects of reducing vibration, further reducing noise and resisting high temperature are achieved; in addition, compared with the prior art that a heavy damping material is paved on the whole tubular structure to be damped, the vibration damping and noise reduction of the tubular structure are realized only by adopting the annular spiral acoustic black hole vibration damping structure, and the light effect is achieved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.
FIG. 1 is a structural diagram of an embodiment of an annular spiral acoustic black hole vibration damping structure of the present invention;
FIG. 2 is a schematic diagram of a one-dimensional acoustic black hole of the present invention;
FIG. 3 is a schematic view of an Archimedes spiral acoustic black hole of the present invention;
FIG. 4 is a schematic illustration of the formation of CSABH in accordance with the present invention;
FIG. 5 is a partial perspective view of the annular spiral acoustic black hole vibration damping structure according to the present invention;
FIG. 6 is a side view of the annular spiral acoustic black hole damping structure of the present invention;
FIG. 7 is a front view of the annular spiral acoustic black hole vibration damping structure of the present invention;
FIG. 8 is a complete perspective view of the annular spiral acoustic black hole vibration damping structure of the present invention;
FIG. 9 is a damping characteristic comparison graph of the homogenizing pipe and the additional annular spiral acoustic black hole vibration damping structure system and the additional contrast group structure system of the homogenizing pipe;
FIG. 10 is a vibration characteristic comparison graph of the homogenizing pipe and the additional annular spiral acoustic black hole vibration damping structure system and the additional contrast group structure system of the homogenizing pipe;
FIG. 11 is a schematic illustration of punching when CSABH is used as the flange;
fig. 12 is a schematic diagram of csalbh as a pipe flange structure connecting two pipes.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
The invention aims to provide an annular spiral acoustic black hole vibration damping structure, which is suitable for vibration damping and noise reduction of a tubular structure and achieves the aims of light weight and high temperature resistance.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
Fig. 1 is a structural diagram of an embodiment of an annular spiral acoustic black hole vibration reduction structure of the present invention, fig. 2 is a schematic diagram of a one-dimensional acoustic black hole of the present invention, and fig. 3 is a schematic diagram of an archimedean spiral acoustic black hole of the present invention. Referring to fig. 1, 2 and 3, the annular spiral acoustic black hole vibration damping structure includes a central circular ring 44 made of a high temperature resistant material, a plurality of archimedean spiral acoustic black holes 1 and a plurality of annular bands 45. The ellipses "... In fig. 1" represent a plurality of archimedean spiral acoustic black holes 1 and a plurality of annular bands 45.
The central ring 44 is sleeved on the surface of the tubular structure A1 to be damped; each Archimedes spiral acoustic black hole 1 is formed by curling the tail end of one-dimensional acoustic black hole 2 around a tubular structure A1 to be damped in an Archimedes spiral mode; all the one-dimensional acoustic black holes 2 are the same; the head end a of each one-dimensional acoustic black hole 2 is fixed on the surface of the tubular structure A1 to be damped through a central ring 44, and the head end a of each one-dimensional acoustic black hole 2 is uniformly distributed in the central ring 44 along the circumferential direction of the tubular structure A1 to be damped; the head end a of the one-dimensional acoustic black hole 2 is the thickest end of the one-dimensional acoustic black hole 2; the tail end b of the one-dimensional acoustic black hole 2 is the thinnest end of the one-dimensional acoustic black hole 2; the thickness of the one-dimensional acoustic black hole 2 decreases exponentially from the head end a of the one-dimensional acoustic black hole 2 to the tail end b of the one-dimensional acoustic black hole 2. The expression of the index is h (x) = epsilon x m +h 0 (ii) a Wherein h (x) represents the thickness of the one-dimensional acoustic black hole 2; ε represents the coefficient; x represents the length of the one-dimensional acoustic black hole 2; m is a constant and is more than or equal to 2; h is 0 The thickness of the thinnest end of the one-dimensional acoustic black hole 2 is shown.
The annular belts 45 are adhered to the outermost layer outline of the Archimedes spiral acoustic black hole 1, and all the annular belts 45 jointly form the outermost layer outline of the annular spiral acoustic black hole vibration reduction structure; the Archimedes spiral acoustic black hole 1 is used for absorbing and dissipating bending vibration energy and torsional vibration energy generated at any position on the tubular structure A1 to be damped; the annulus 45 is used to dissipate bending and torsional vibration energy.
Wherein, the number of the Archimedes spiral acoustic black holes 1 is at least 4. The number of the endless belts 45 is at least 4. The number of the Archimedes spiral acoustic black holes 1 is equal to the number of the annular bands 45.
Specifically, the endless belt 45 is a damping material. The damping material is 3M damping material.
The central ring 44 is fixed to the surface of the tubular structure A1 to be damped by gluing or welding. The head end a of each one-dimensional acoustic black hole 2 is fixed on the surface of the tubular structure A1 to be damped and is connected into a whole through a central ring 44. The one-dimensional acoustic black holes 2 are connected together by a central ring 44.
As an alternative embodiment, the central ring 44 is provided with bolt holes; the bolt holes are used for fixedly connecting two tubular structures A1 to be damped.
The technical scheme of the annular spiral type acoustic black hole vibration reduction structure is described in detail by a specific embodiment as follows:
the annular Spiral Acoustic Black Hole vibration reduction structure provided by the invention is based on the low fundamental frequency, high modal density and high matching degree with the inherent frequency of a main structure of the annular Spiral Acoustic Black Hole (CSABH), can generate a dynamic vibration absorption effect in a wider frequency domain, improves the coupling effect of the Acoustic Black Hole and the main structure, improves the loss factor of the structure, further restrains the vibration energy of the structure and achieves the effect of broadband vibration reduction. As the CSABH is connected with the pipeline through the circular ring (the central circular ring 44), the contact surface covers the circumferential surface of the whole pipeline structure, and the bending vibration and the torsional vibration energy generated at any position on the pipeline can be absorbed and dissipated, thereby achieving the aim of multi-directional vibration reduction.
1. Surface formula of CSABH
The csalbh is obtained by arraying k csalbh 1 around the circle center O, taking a single csalbh as a research object, and establishing a polar coordinate system (r, θ) with O as an origin, as shown in fig. 3. Wherein R is the helical outer ring radius; r is the helical inner circle radius; n is the number of revolutions of the spiral; θ is the rotation angle. The curve equation is as follows:
r(s)＝R-(R-r)s
q(s)＝2πns
s∈[0,1]
where q represents how many degrees the spiral has rotated from the start point to the end point and s represents a variable defining the radius of each point on the spiral.
The function of the curve equation is to describe the curve of the spiral-shaped ABH area on the CSABH, and the parameters in the equation are changed to adjust and design the CSABH structure. Wherein the Archimedes spiral ABH1 profile, as shown in FIG. 3The one-dimensional ABH2 contour is formed by curling the one-dimensional ABH2 contour of the graph 2 in the form of Archimedes spiral, the parameters of the variable thickness area are the same as those of the one-dimensional ABH2 variable thickness area, and the one-dimensional ABH2 variable thickness area satisfies h (x) = epsilon x m +h 0 . The solid line portions in fig. 3 and 2 are both the variable thickness regions, that is, the ABH regions are both variable thickness. Fig. 3 and 2 illustrate csbh surfaces.
2. Formation of CSABH
The CSABH for the research example of the invention is obtained by arranging 4 Archimedes spiral ABH1 around a circle center O, namely, taking an example that an annular spiral acoustic black hole vibration damping structure comprises 4 Archimedes spiral acoustic black holes, the annular spiral acoustic black hole vibration damping structure is explained in detail, the forming process of the annular spiral acoustic black hole vibration damping structure is shown in figure 4, figure 4 is a CSABH structure schematic diagram, namely a CSABH forming schematic diagram, part (a) in figure 4 shows an Archimedes spiral ABH schematic diagram, part (b) in figure 4 shows four Archimedes spiral ABH schematic diagrams, and part (c) in figure 4 shows the formed CSABH schematic diagram. The csambh forming process is performed by one archimedean spiral ABH, as shown in the solid line portion of portion (a) of fig. 4, and the other three are arrayed around the dashed circular ring (central circular ring 44), and it is understood that the other three are duplicated by one archimedean spiral ABH rotating around the dashed circular ring, and form 4 archimedean spirals ABH together with the other three, as shown in the solid line portion of portion (b) of fig. 4. Part (a), (b), and (c) of fig. 4 illustrate the csbh formation (modeling) process, and part (b) of fig. 4 is a perspective view of part (c) and is also an array process of part (a). When CSABH is completely formed, that is, in the form of the portion (c) in fig. 4, the a-end portion (thick portion) of the archimedean spiral ABH and the dotted circle in the middle of the portions (a) and (b) in fig. 4 are integrated at the time of final forming, and thus the representation of the portion (c) in fig. 4 does not need to be shown again. The dotted circle is true, in the sense that the 4 archimedean spiral ABH pairs are joined to form a whole and mounted on the tubular structure A1 to be damped. The merged state means that the final csbh (damping free) is presented in a real-object front view in the form of a representation shown in part (c) of fig. 4, and the existence of the dashed circle cannot be directly seen by the naked eye. The 4 archimedean spirals ABH are connected as a whole by the central ring 44, forming a structure, namely csambh structure, the front view of which without damping is of the form shown in part (c) of fig. 4. In addition, the a end parts of the Archimedes spiral ABH do not need to be separated by a quarter of a circular arc, the invention is discussed by taking the separated quarter of a circular arc as an example, and the specific separation can be self-drawn according to the needed research object.
3. Vibration damping of CSABH
Fig. 5 is a partial perspective view of the annular spiral acoustic black hole vibration reduction structure of the present invention, fig. 6 is a side view of the annular spiral acoustic black hole vibration reduction structure of the present invention, fig. 7 is a front view of the annular spiral acoustic black hole vibration reduction structure of the present invention, and as shown in fig. 5, fig. 6, and fig. 7, the annular spiral acoustic black hole vibration reduction structure A2 of the present invention includes: a central circular ring 44 and an Archimedes spiral ABH around the central circular ring 44, and an annular spiral type acoustic black hole vibration damping structure A2 is arranged on a controlled structure (tubular structure to be damped) A1.
The central ring 44 is composed of a second circle 42 (i.e. the outer wall 42 of the pipeline) and a third circle 43, the inner diameter of the pipeline of the controlled structure A1 is a first circle 41, the outer diameter of the pipeline is the second circle 42, the centers of the first circle 41, the second circle 42 and the third circle 43 are the same, and the second circle 42 and the third circle 43 are on the same plane.
The annular spiral type acoustic black hole vibration reduction structure A2 is connected with the controlled structure A1 through a second circle 42. The second circle 42 is the outer wall of the pipeline, no holes need to be punched in the outer wall of the pipeline, and the second circle 42 is common to the pipeline and the CSABH and is the outer wall of the pipeline and the inner wall of the CSABH. When the vibration reduction structure A2 is connected with the controlled structure A1, the CSABH can be sleeved on the pipeline, and the contact surfaces of the vibration reduction structure A2 and the controlled structure A1 are connected in a gluing or welding mode.
The thickness of the acoustic black hole portion (archimedean spiral ABH) decreases exponentially with the thickness of the one-dimensional ABH, and the one-dimensional ABH is bent into an archimedean spiral form around the central circular ring 44. Wherein, the thickness of the acoustic black hole part is the thickness of the one-dimensional ABH. The exponential expression is h (x) = epsilon x m +h 0 Wherein h (x) represents the thickness of the acoustic black hole portion (thickness of the variable thickness region), ε represents a coefficient, x represents the length of the one-dimensional ABH, m.gtoreq.2, h 0 Indicating the minimum thickness of the acoustic black hole portion. The determination method of the epsilon comprises the following steps: firstly, the minimum thickness h of the acoustic black hole part in the figure 2 is determined according to the requirement 0 And the maximum thickness h of the acoustic black hole part 1 Then points are substituted into the expression h (x) = epsilon x according to the xy coordinate system in fig. 2 m +h 0 The coefficients are obtained by an equation.
The annular spiral type acoustic black hole vibration damping structure further comprises an annular belt 45, and the annular belt 45 is used for consuming most of elastic wave energy (vibration energy). The ring belt 45 is made of damping material, and the ring belt 45 is adhered to the contour of the Archimedes spiral ABH and is adhered to the position with the minimum thickness to the position with the maximum thickness by a proper length. The damping does not need to be pasted above the outline of the whole Archimedes spiral ABH, the ABH can be pasted from the minimum thickness position to the maximum thickness position, the specific length of the pasted damping girdle band can be set by self, theoretically, the more the damping pasting is better, but in order to lighten the mass, only a small part is pasted to achieve the ideal vibration reduction effect.
Specifically, the damping material of the endless belt 45 is a 3M damping material.
The annular spiral type acoustic black hole vibration damping structure is based on the fact that elastic waves in a solid medium are reduced along with the thickness of the structure according to a certain power-power function, the corresponding phase velocity and group velocity are also reduced, and therefore broadband elastic waves are gathered in a thickness thinning area on a certain spatial scale, as shown in figure 5, vibration energy on a controlled structure A1 can be transferred to an annular spiral type acoustic black hole vibration damping structure A2 through a central circular ring 44. In an acoustic black hole region (archimedean spiral ABH) of the annular spiral acoustic black hole vibration attenuation structure A2, the wave propagation speed is reduced along with the reduction of the thickness, the wavelength is reduced, the vibration amplitude of the wave is increased, and the wave is gathered to the region with the reduced thickness, and most of the elastic wave energy is consumed by combining the damping material 45, so that the purposes of high-efficiency energy absorption or vibration attenuation and noise reduction are achieved.
In addition, when the annular spiral acoustic black hole vibration reduction structure is used for realizing vibration reduction and noise reduction of the tubular structure, the number of the annular spiral acoustic black hole vibration reduction structures can be selected according to actual conditions, and the vibration reduction and noise reduction of the tubular structure can be realized by only using one annular spiral acoustic black hole vibration reduction structure, but considering that the vibration mode of the controlled pipeline in the embodiment has symmetry, if the annular spiral acoustic black hole vibration reduction structure is arranged in a region on the left end, the vibration suppression effect on the left end of the pipeline is the best, and similarly, the annular spiral acoustic black hole vibration reduction structure is arranged in a region on the right end and the right end of the pipeline and has the best vibration suppression. Therefore, in order to control the vibration of the whole pipeline and achieve the best effect of vibration control, the annular spiral acoustic black hole vibration damping structure is preferably arranged at the position with the largest vibration displacement at the two ends of the pipeline respectively. The annular spiral type acoustic black hole vibration reduction structure is required to be arranged at the position with the maximum displacement when the pipeline vibrates in principle.
Fig. 8 is a perspective view of the annular spiral acoustic black hole vibration reduction structure of the present invention, that is, a complete perspective view of the annular spiral acoustic black hole vibration reduction structure. As shown in FIG. 8, a hollow uniform pipe structure with a length of 1700mm, an outer diameter of 66mm and an inner diameter of 60mm is used as a controlled object (controlled structure) A1. Two spiral acoustic black holes (CSABH) are attached to the two ends of the hollow pipeline. The annular spiral type acoustic black hole vibration reduction structure comprises a central annular ring, wherein the diameter of a second circle is 66mm, and the diameter of a third circle is 75mm. The radius R of the outer ring of the spiral is 63.5mm, the radius R of the inner ring of the spiral is 37.5mm, the revolution number n of the spiral is 1, and the rotation angle theta is 0 deg. Minimum thickness h of acoustic black hole area part (Archimedes spiral ABH) 0 0.5mm, maximum thickness h 1 And 4.5mm. The hollow round pipeline material is made of aluminum, and the annular spiral acoustic black hole material is made of photosensitive resin. The annular spiral acoustic black hole vibration reduction structure further comprises an annular belt 45, the annular belt 45 is made of damping materials, the length of the annular belt 45 is 83.56mm, the width of the annular belt is 20mm, the thickness of the annular belt is 1mm, 3M damping materials are selected for arrangement, and a material loss factor (loss factor) is set to be 0.2. Meanwhile, for comparison research, an annular spiral structure with the same quality and uniform thickness is designed to serve as a comparison group. Wherein the masses are identicalA Circular Spiral type structure of uniform thickness, i.e., circular Spiral type Equal Mass structure (CSEM).
The width of the annular damping material is the same as that of CSABH, the thickness is 1mm determined according to the thickness of the common damping material in practice, the sticking thickness does not exceed the black hole area, and more damping materials are selected to be stuck without adding excessive extra mass.
A model of the annular spiral acoustic black hole vibration damping structure is established in ABAQUS by adopting a finite element method, and the damping level and the vibration speed response of the annular spiral acoustic black hole vibration damping structure are calculated by a steady-state dynamics analysis and a modal superposition method.
And (4) analysis of calculation results:
(1) Damping characteristic analysis
As shown in FIG. 9, the annular spiral acoustic black hole vibration attenuation structure can greatly improve the inherent damping level of the structure, and the system damping is improved by 5-80 times compared with the full frequency band. Compared with an even annular spiral structure (annular spiral equal-mass structure) with equal mass, the inherent damping level of CSABH is obviously increased because the property of the resin material is improved by 1-20 times. The system damping ratio of CSABH is increased by times compared with the control group in the whole frequency band range of 100Hz-5000 Hz. In summary, the csambh structure can greatly improve the damping characteristic of a uniform pipeline structure, and is more advantageous than an annular spiral structure (annular spiral type equal-mass structure) with equal mass, which has potential benefits for suppressing the vibration of an elastic structure, and meanwhile, the controlled object cannot be damaged due to lighter mass.
(2) Vibration control characteristic analysis
As shown in fig. 10, in order to evaluate the vibration level of the system, the origin response of the system was selected as an index for evaluation. It can be found from fig. 10 that, after the annular spiral acoustic black hole vibration damping structure of the present invention is added, compared with the structure before being controlled, the resonance peak of 8-35dB is reduced for all frequencies in the whole frequency band range, because the annular spiral acoustic black hole vibration damping structure of the present invention has good directivity and robustness due to the acoustic black hole effect, the dynamic vibration absorption effect and the torsional mode generated by the spiral design, so that the annular spiral acoustic black hole vibration damping structure has a very high modal damping ratio, and can adapt to the vibration energy transmitted from multiple directions in a wider frequency band range, exert the vibration damping characteristic thereof, absorb the vibration energy on the controlled structure, and reduce the vibration level of the system. In addition, compared with a system added with an equal-mass annular spiral structure (annular spiral equal-mass structure), the annular spiral acoustic black hole structure added with the method has the vibration attenuation of 0-26dB at a full-band formant position compared with the system added with the equal-mass annular spiral structure, and the reason is that the design that the edge of the annular spiral acoustic black hole structure is thickened changes the impedance of the structure, so that the propagation speed of elastic waves in the structure is gradually reduced, and the vibration energy is concentrated in the minimum thickness area of the structure. By combining a small amount of damping materials in the energy concentration area, the structural loss factor can be effectively enhanced, the energy can be absorbed, and the structural vibration can be reduced.
The annular spiral acoustic black hole vibration attenuation structure ingeniously combines the characteristics of the acoustic black hole structure, the dynamic vibration absorber structure and the Archimedes spiral structure, avoids the limitations that the traditional acoustic black hole can only control a plate-shaped structure in vibration control and the direction of elastic wave control is limited, improves the modal density of the structure on the premise of saving space due to the spiral design, can realize the control of multiple modes of a controlled object by a single device, and achieves the efficient vibration attenuation effect. The invention can carry out parameter design according to the frequency characteristic of the controlled object and the like, and can further improve the broadband characteristic.
The annular spiral acoustic black hole vibration damping structure has the advantages of being small in additional mass, easy to meet engineering application and high in efficiency.
The annular spiral acoustic black hole (CSABH) structure, namely the annular spiral acoustic black hole vibration damping structure, provided by the invention can widen the frequency band range of ABH by designing ABH into a spiral structure, and increases the directivity of ABH to vibration control. Meanwhile, the connection design of the central ring 44 and the pipe wall (tubular structure outer wall) also increases the contact surface between the ABH and the pipeline (tubular structure), ensures that the vibration on the pipeline is comprehensively transmitted to the acoustic black hole area above the ring, achieves the purpose of broadband and multidirectional vibration reduction, and not only is effective on radial vibration perpendicular to the pipeline direction in controlling the vibration, but also solves the problem that the common acoustic black hole can not control circumferential vibration around the pipeline direction. And a bolt hole is drilled at the central ring 44, that is, a new flange structure is drilled on the csbh to replace the conventional flange structure, as shown in fig. 11, so that the annular spiral acoustic black hole structure (annular spiral acoustic black hole vibration damping structure) can replace the conventional flange structure for connecting a pipeline and a pipeline, and the flange structure can be used for damping vibration. The central ring 44 is perforated to connect two pipes instead of a flange structure, and if the damping function of csab is used only, the pipes can be sleeved by gluing, welding or the like without perforation, and if the pipes are perforated as flanges, see fig. 11. A schematic diagram when csalbh is used as a pipe flange structure to connect two pipes is shown in fig. 12.
The annular spiral acoustic black hole (CSABH) structure can be made of high-temperature-resistant materials, and achieves the purposes of light weight, high temperature resistance and broadband vibration reduction by combining the characteristics of vibration reduction and noise reduction of the acoustic black hole. The vibration reduction and noise reduction of the acoustic black hole are realized by transmitting the vibration energy on the pipeline to a variable thickness area of a CSABH structure and combining the vibration energy with the damping material adhered to the variable thickness area to achieve the effect of reducing vibration and further reducing noise, so that the problem of vibration reduction and noise reduction of a tubular structure is solved. Compared with a controlled main structure (a tubular structure to be damped), the structure of the invention has light weight, and by taking the example of the invention, the two CSABHs are installed to achieve good damping effect, namely the mass of the main structure is increased by 5.6%, while the traditional damping for the pipeline usually adopts a heavy damping material paved on the whole pipeline, and the additional mass of the damping material is usually more than 10%, so the structure of the invention can achieve the light weight effect.
Compared with the prior art, the invention has the following advantages:
1. the conventional acoustic black hole structure is designed in a spiral form and can be applied to a piping system by combining a ring structure.
2. The outer ring acoustic black hole part of the annular spiral acoustic black hole is designed into a spiral form, so that the directionality of vibration control on the pipeline structure can be increased.
3. The acoustic black hole part is designed into a spiral form, so that the modal density can be improved on the premise of saving the installation space, the coupling effect of the ABH and the main structure is enhanced, the loss factor of the structure is greatly improved in a wide frequency range, and the frequency band range of vibration control is widened.
4. The annular spiral acoustic black hole is mainly designed by combining three main structures, namely an acoustic black hole, a dynamic vibration absorber and an Archimedes spiral structure.
5. The acoustic black hole is designed to be applicable in the form of a ring of the pipe structure.
6. The annular spiral acoustic black hole can be used as a novel flange structure with a vibration reduction function to establish connection between pipelines.
CSABH was derived from a single helical ABH (Archimedes spiral ABH) arrayed k around the center of a circle. Usually k is more than or equal to 4, and the essential principle and the vibration reduction mechanism of the structure formed by other numbers of the array are completely the same as those mentioned in the invention.
8. The annular spiral acoustic black hole (CSABH) structure can be made of various materials such as high temperature resistance and the like, can adapt to various complex working conditions of pipeline working, and avoids the situation that the vibration reduction structure is damaged under severe working conditions. And due to the characteristics of the acoustic black hole structure, the purposes of light weight, high temperature resistance and broadband vibration reduction can be achieved.
9. The annular spiral acoustic black hole (CSABH) structure can be used as a flange structure of a pipeline to be installed on the pipeline, can replace the traditional flange structure, and avoids the problem that other unnecessary vibration reduction structures are added to the pipeline for vibration reduction.
In the present specification, the embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.
Claims (9)
1. The annular spiral acoustic black hole vibration damping structure is characterized by comprising a central ring, a plurality of Archimedes spiral acoustic black holes and a plurality of annular belts, wherein the central ring is made of a high-temperature-resistant material;
the central ring is sleeved on the surface of the tubular structure to be damped; each Archimedes spiral acoustic black hole is formed by curling the tail end of one-dimensional acoustic black hole around the tubular structure to be damped in an Archimedes spiral mode; all the one-dimensional acoustic black holes are the same; the head end of each one-dimensional acoustic black hole is fixed on the surface of the tubular structure to be damped through the central ring, and the head end of each one-dimensional acoustic black hole is uniformly distributed in the central ring along the circumferential direction of the tubular structure to be damped; the head end of the one-dimensional acoustic black hole is the thickest end of the one-dimensional acoustic black hole; the tail end of the one-dimensional acoustic black hole is the thinnest end of the one-dimensional acoustic black hole; the thickness of the one-dimensional acoustic black hole decreases exponentially from the head end of the one-dimensional acoustic black hole to the tail end of the one-dimensional acoustic black hole;
the annular belts are adhered to the outermost layer contour of the Archimedes spiral acoustic black hole, and the annular belts jointly form the outermost layer contour of the vibration damping structure; the Archimedes spiral acoustic black hole is used for absorbing and dissipating bending vibration energy and torsional vibration energy generated at any position on the tubular structure to be damped; the annulus is configured to dissipate the bending vibration energy and the torsional vibration energy.
2. The annular spiral acoustic black hole damping structure of claim 1, wherein the number of the Archimedes spiral acoustic black holes is at least 4.
3. The annular spiral acoustic black hole damping structure of claim 1, wherein the number of annuli is at least 4.
4. The acoustic annular helical black hole vibration damping structure of claim 1, wherein the number of the acoustic black holes of the archimedean spiral and the number of the annular bands are equal.
5. The toroidal helical acoustic black hole vibration damping structure according to claim 1, wherein an expression of said exponent is h (x) = ε x m +h 0 (ii) a Wherein h (x) represents the thickness of the one-dimensional acoustic black hole; ε represents the coefficient; x represents the length of the one-dimensional acoustic black hole; m is a constant and is more than or equal to 2; h is a total of 0 And the thickness of the thinnest end of the one-dimensional acoustic black hole is represented.
6. The annular spiral acoustic black hole vibration damping structure of claim 1, wherein the annulus is a damping material.
7. The annular spiral acoustic black hole vibration damping structure of claim 6, wherein the damping material is a 3M damping material.
8. The annular spiral acoustic black hole vibration damping structure according to claim 1, wherein a bolt hole is provided on the central ring; the bolt holes are used for fixedly connecting the two tubular structures to be damped.
9. The annular spiral acoustic black hole vibration damping structure of claim 1, wherein the central ring is fixed to the surface of the tubular structure to be damped by gluing or welding.
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Cited By (2)
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| CN116341222A (en) * | 2023-03-09 | 2023-06-27 | 南京理工大学 | Method for designing acoustic black hole dynamic vibration absorber with tree-shaped structure |
| CN116497959A (en) * | 2023-04-28 | 2023-07-28 | 威海克莱特菲尔风机股份有限公司 | Perforated roll paper structure with high sound absorption performance and preparation method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116341222A (en) * | 2023-03-09 | 2023-06-27 | 南京理工大学 | Method for designing acoustic black hole dynamic vibration absorber with tree-shaped structure |
| CN116341222B (en) * | 2023-03-09 | 2024-05-28 | 南京理工大学 | Method for designing acoustic black hole dynamic vibration absorber with tree-shaped structure |
| CN116497959A (en) * | 2023-04-28 | 2023-07-28 | 威海克莱特菲尔风机股份有限公司 | Perforated roll paper structure with high sound absorption performance and preparation method |
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